The present invention relates generally to an agricultural mixing apparatus and more particularly to a grinder-mixer having a trough-shaped tank and two augers for transferring and intermixing material.
Existing agricultural grinder-mixers typically reduce feed material to a particular size, transfer it to a mixing tank wherein various feed additives are introduced and then mix and recirculate the feed and additives in preparation for discharge into hog self feeders, cattle feed bunkers or a feed storage container. Such implements usually include a mixing tank, material-reducing mill, feed additive hopper connected with the tank and several auger conveyors including a first transfer auger for moving material from the reducing mill to the tank, a second auger for moving material from the additive hopper to the tank, a third auger for elevating the material within the tank and a fourth auger for unloading material from the tank. Many machines require three additional augers to move material and deposit it into hog self feeders, cattle feed bunkers or feed storage containers.
In operation, these grinder-mixers first process the material in a hammer mill or similar unit and then transfer it to the mixing tank. Feed additives introduced by the farmer or operator into the additive hopper are also conveyed to the mixing tank. The mixing tank contains a vertical auger adapted to receive material at its lower portion, elevate it and discharge it back into the tank wherein it settles again to the bottom and is again recirculated by the vertical auger. After the ground materials and additives are completely intermixed, the unloading auger conveyor transfers the material from the tank and to feed bunkers or other appropriate storage containers.
Conventional grinder-mixers include tank configurations similar to the conical, cylindrical and flat-sided tanks illustrated respectively in U.S. Pat. No. 3,840,189 to Kaniengieter et al issued Oct. 8, 1974, U.S. Pat. No. 3,667,734 to Skromme et al issued June 6, 1972 and U.S. Pat. No. 2,894,733 to Wosmek issued July 14, 1959. A problem sometimes encountered during operation with grinder-mixers having downwardly converging tanks such as illustrated in Kaniengieter and Wosmek is that certain material may bridge as it settles in the lower portion of the tank. This occurs since the cross-sectional area of the tank decreases as the walls converge inwardly and the settling material becomes compressed resulting in a solid bridge of material being accumulated between the tank wall and the auger housing carried in the center of the tank. When a bridge is formed, other material is prevented from settling and eventually a void forms around the inlet area of the vertical mixing auger thereby requiring that the mixing process be stopped until the bridge of material is loosened. As a result, productivity and capacity are reduced. The bridging problem is overcome for the most part in the cylindrical tank configuration illustrated in Skromme et al. Nevertheless, material occasionally compacts around the lower tank walls outwardly of and below the sweeping and cleaning blade. Torque requirements for driving the sweep blade are then increased and material flow through the inlet and outlet openings in the bottom of the tank is reduced.
A further problem with existing grinder-mixers results from the multiple mixing and transfer augers or conveyors utilized. To operate several conveyors, a substantial power train structure capable of transmitting the necessary power to each conveyor must be provided and thus the initial manufacturing and later maintenance expenses are increased.